When a drug is administered by instillation to the eye, a therapeutically effective concentration of the drug can be generally transferred comparatively easily into anterior ocular tissues such as cornea, aqueous humor and the like and external ocular tissues such as lacrimal fluid, conjunctiva and the like. However, it is difficult to transfer a drug to posterior ocular tissues such as retina, choroid, sclera, vitreous body and the like, which are located posterior to the crystalline lens, by instillation to the eye. In addition, oral administration, intravenous injection and the like can be employed as administration methods of a drug to posterior ocular tissues. However, since they are used for systemic administration where a drug is delivered to posterior ocular tissues via systemic circulation of blood, side effects at the site other than the target tissue are feared.
As a new form for intraocular administration of an ophthalmic pharmaceutical agent, patent document 1 proposes an intraocular medicament administration device wherein a flat plane formed from a hydrogel material has a ring shape. However, since the intraocular medicament administration device has a flat shape, stable wearing thereof in the interior of the eye is difficult.
In addition, patent document 2 proposes a ring-shaped device designed to fit the curvature of the eye, which contains a biocompatible material and an ophthalmic drug. The ring-shaped device is placed on the ocular surface without covering cornea but surrounding the cornea and covering a surgery incision site on the sclera in the anterior eye region, and the drug is released from the device to the sclera incision site. However, the intraocular stability while being worn on the eye cannot be afforded only by considering the eye curvature.
In addition, there is no report on the delivery of a drug in a drug-containing ring-shaped device to posterior ocular tissues using the device.